(1) Field of the Invention
The present invention relates to a device for use in an elastomeric vehicle launching system, and more particularly to an elastomeric disk for the storage of elastic energy convertible to impulse fluid energy with the impulse fluid capable of ejecting or launching vehicles from the system into a liquid medium.
(2) Description of the Prior Art
Impulse fluid flows are used to launch vehicles from submarine platforms. Elastomeric ejection systems have been developed which store impulse fluid in a charged elastomeric bladder or against the pressure surface of a distended elastomeric disk. In the operation of an ejection system with an elastomeric disk, a recharge pump of the system draws water from the ocean such that the inflow of water has a pressure that distends or expands the disk. The elastic deformation of the disk by expansion results in a storage of energy by the disk. Once a predetermined amount of energy is stored, the recharge pump is shut off.
In order to launch a vehicle, a slide valve for the designated torpedo tube is opened. The opening action of the slide valve allows instantaneous porting water from the expanded disk to the torpedo tube with the porting water pressure capable of launching weapons from the tube.
Typical disks used for elastomeric ejection systems have a flat, ellipsoidal, spherical, or other symmetrically contoured shape. The purpose of a symmetrical contoured shape is to distribute strain energy across the disk during expansion. For example, the prior art disk 2 shown in FIG. 1 and shown in the cross-sectional view of FIG. 2 has a symmetrical contour about a central plane 4. When the prior art disk 2 expands, as shown in FIG. 3, the expansion of the disk 2 outward is the greatest at the center axis 6 of the disk 2. The disk 2 must be clamped or attached at its edges 8, 10 to the supporting structure 12 in order to expand outward.
The problem with the clamping of the disk 2 to the supporting structure 12 is that the expansion of the disk consequently puts a significant material strain at the periphery of the disk 2. While there is a contact strain with the supporting structure 12, the material strain is greater on the pressure surface 14 of the disk 2 specifically at the point 16 where the disk 2 bends toward deformation of the disk. This material strain at the bend of the disk 2 significantly increases the risk of disk failure during operation and interferes with the distribution of material strain across the disk 2. In addition, the variation in the clamping strength of the supporting structure 12 and the loss of material strength of disk 2 at the structure 12 makes it difficult to predict how many cycles of operation the disk 2 can safely withstand.
Accordingly, it is a general purpose and primary object of the present invention to provide an elastomeric disk resistant to cyclic material failure at its periphery.
It is a further object of the present invention to provide an elastomeric disk in which the peak material strain levels of the disk are located proximate to the center of the disk such that the cycles of operation for the disk can be adequately determined.
It is a still further object of the present invention to provide an elastomeric disk which securely attaches to the structure of an elastomeric ejection system.
To attain the objects described there is provided an elastomeric disk with a thickened curvature protruding from both sides of a central plane of the disk. Integral to each curvature of the disk is an annulet which dovetails from the curvatures to a periphery of the disk. The annulet allows secure attachment of the disk to the ejection system preferably by a clamp of the supporting structure of the ejection system.
In contrast to the prior art, the contour of the disk is asymmetrical at the periphery of the disk. Specifically, the thickness of the annulet in regard to the central plane is greater on the pressure side of the disk. By increasing the thickness of the annulet on the pressure side of the disk, the bending strain and resultant material strain on the disk caused by expansion is compensated for while the holding action of the clamp is maintained. The strengthening of the disk thereby lengthens the material cyclic life of the ejection system since fatigue problems associated with the material strain at the periphery bend are minimized. In addition, the reduction of material strain at the periphery has the result of relocating the higher material strain away from the clamp and towards the center axis of the disk. At the center portion of the disk, incidence of fatigue failure is generally expected and thus a fatigue failure becomes more predictable for maintenance scheduling.
The above and other features of the invention, including various and novel details of construction and combinations of parts will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular devices embodying the invention are shown by way of illustration only and not as the limitations of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.